Source : Webster's Revised Unabridged Dictionary (1913)

Fir \Fir\ (f[~e]r), n. [Dan. fyr, fyrr; akin to Sw. furu, Icel.
   fura, AS. furh in furhwudu fir wood, G. f["o]hre, OHG. forha
   pine, vereheih a sort of oak, L. quercus oak.] (Bot.)
   A genus ({Abies}) of coniferous trees, often of large size
   and elegant shape, some of them valued for their timber and
   others for their resin. The species are distinguished as the
   {balsam fir}, the {silver fir}, the {red fir}, etc. The
   Scotch fir is a {Pinus}.

   Note: Fir in the Bible means any one of several coniferous
         trees, including, cedar, cypress, and probably three
         species of pine. --J. D. Hooker.

Source : WordNet®

fir
     n 1: nonresinous wood of a fir tree
     2: any of various evergreen trees of the genus Abies; chiefly
        of upland areas [syn: {fir tree}, {true fir}]

Source : Free On-Line Dictionary of Computing

FIR
     
        1.  {Finite Impulse Response} (filter).
     
        2.  Fast Infrared.  {Infrared} standard from {IrDA},
        part of {IrDA Data}.  FIR supports {synchronous}
        communications at 4 Mbps (and 1.115 Mbps?), at a distance of
        up to 1 metre.
     
        (1999-10-14)